1. Field of the Invention
This invention relates to a cassette loading device which has a cassette holder movable between a cassette inserting position and a cassette loading position, by which a cassette that is inserted in the cassette holder at the cassette inserting position is conveyed downward to the cassette loading position so as to be put on a positioning means disposed in the cassette loading position, and which is most suitably used for a cassette tape recording and/or reproducing apparatus, such for example, as a cassette video tape recorder.
2. Description of the Prior Art
In a conventional cassette loading device illustrated in FIGS. 1A to 2C, a cassette holder 1 comprises a bottom plate 1a, a pair of right and left side plates 1b and a top plate 1c arranged so as to form a rectangular section.
The cassette holder 1 is driven by a lifting mechnism (not shown) between a cassette inserting position shown in FIGS. 1A, 2A and a cassette loading position lying thereunder shown in FIGS. 1B, 2B in direction of arrows a and b, that is, along an inverted L-shaped route.
When loaded, a cassette 3 is inserted horizontally in direction of arrow C as shown in FIG. 1A through a cassette inserting aperture 5 opening in a front panel 4 into the cassette holder 1 which is to return to the cassette inserting position.
On this occasion, a front end face 3a of the cassette 3 abuts on a stopper 6 disposed at one end of the bottom plate 1a of the cassette holder 1 to put the cassette 3 in proper position and, as illustrated in FIG. 2B, a guide groove 7 formed along the center line of a bottom face 3b of the cassette 3 is engaged with a rail 8 formed along the center line of the bottom plate 1a of the cassette holder 1 so as to prevent the cassette 3 from being inserted inversely or upside-down and to provide proper positioning of the cassette 3 in a right to left orientation. In addition as illustrated in FIGS. 1A and 1B, a cassette pressing mechanism 11 which comprises a plurality of rollers 9, a leaf spring 10, etc. is disposed in the top plate 1c of the cassette holder 1 to resiliently urge the inserted cassette 3 down against the bottom plate 1a of the cassette holder 1.
After an insertion of the cassette, the cassette holder 1 is moved horizontally backward and then vertically downward in direction of arrow a shown in FIG. 1A to the cassette loading position by the lifting mechanism so as to engage a pair of right and left reels (not shown) within the cassette 3 with a pair of reel tables (not shown) on a chassis 12 in the cassette loading position as shown in FIGS. 1B, 2B.
On this occasion, the bottom face 3b of the loaded cassette 3 is put on a positioning means, which comprises a plurality of positioning pins 13 which are built in a chassis 12 and extend upwardly through the bottom plate 1a of the cassette holder 1 so as to from a gap A between the bottom face 3b of the cassette 3 and the bottom plate 1a of the cassette holder 1 and pressed down by the leaf spring 10 of the cassette pressing mechanism 11 for positioning the cassette 3.
By the way, the operation to take out the cassette 3 from the cassette holder 1 is accomplished by reversing the above operation, whereas the cassette holder is moved vertically upward and then horizontally forward in the direction of arrow b shown in FIG. 1A.
The conventional cassette loading device constituted as mentioned above has a defect as follows:
Lest a top face 3c of the cassette 3 should abut on the top plate 1c of the cassette holder 1 when the cassette 3 is set in the cassette loading position as illustrated in FIGS. 1B, 2B and separated by the predetermined gap A within the cassette holder 1 from the bottom plate 1a by the positioning pins 13, a predetermined gap B is necessary between the top face 3c and the top plate 1C, so that when the cassette 3 is inserted in the cassette holder 1 in the direction of arrow c as shown in FIGS. 1A, 2A, a conspicuously large gap C which is a sum of the gaps A and B is formed between the top face 3c of the cassette 3 and the top plate 1C of the cassette holder 1.
On the other hand, the larger a depth D of the guide groove 7 in the bottom face 3b of the cassette 3 becomes, the larger a thickness of the cassette 3 becomes. Hence, the rail 8 of the cassette holder 1 can not be so tall but must be generally less than gap C.
Such being the case, the bottom face 3b of the cassette 3 often runs on to the rail 8 of the cassette holder 1 as shown in FIGS. 1C, 2C because of the improper insertion of the cassette 3 into the cassette holder 1, so that it becomes impossible to prevent the cassette 3 from erroneous insertion and incorrect positioning in its right to left orientation.
As illustrated in FIGS. 1B, 2B to press stably the cassette 3 on the positioning pins 13 in the cassette loading position for positioning the cassette 3, it is important to have the cassette 3 pressed in a middle portion in a front to rear orientation of the cassette 3 and that in properly spaced, well-proportioned position in a right to left orientation of the cassette 3 by the cassette pressing mechanism 11.
Therefore, to press always stably each of the cassettes 3 on the pressing pins 13 even if the inserted cassettes 3 are different in sizes from one another, such for example, as shown by a solid line, dot-and-dash line and double-dots-and-dash line in FIGS. 2A, 2B, it is necessary to include a plurality of cassette pressing mechanisms suitable for the cassettes 3 of various sizes, respectively. Such causes to make a construction of the upper portion of the cassette holder 1 very complicate, the cassette dear and the inside of the cassette more crowded.